1. Field of the Invention
The invention relates to a method and a system for rendering an image, more particularly to a method and a system for rendering an image from a light-field camera.
2. Description of the Related Art
In recent years, light fields have been introduced into computer graphics and have been applied in many domains of our daily lives. Some companies now produce light-field cameras for different applications. A major technique of a light-field camera resides in an array of microlenses arranged between a main lens and a photosensor in a camera. Each of the microlenses is equivalent to a camera lens disposed at a distinct position. Each of the microlenses forms on the photosensor a respective micro-image which is composed of a plurality of pixels recording directions and intensities of light rays. Information associated with the directions and intensities is recorded by the same photosensor behind the array of microlenses with respect to the main lens. Computer software may be adopted to process the information so as to generate light-field data, such that a focus position of an image captured by a light-field camera may be changed arbitrarily based on the light-field data.
However, each time the focus point over the image is changed, all pixels of the image are usually required to undergo refocusing operations. Moreover, optical/mechanical autofocusing has its limitations on focusing speed. A current optical focusing system usually requires about 0.09 second to focus, which is substantially equal to the time period of three frames of motion pictures. Accordingly, for the purpose of effectively reducing unnecessary refocusing operations, solutions to overcome the aforementioned issues need to be found.